In the insulation industry, felts of mineral fibers, such as fine diameter glass fibers, are formed into strips which are to be used for the thermal and/or acoustical insulation of buildings and other structures or apparatus. These glass fiber felts are low in density and comprise fine glass fibers which entrap air in dead air pockets to achieve the thermal and acoustical insulating properties desired. The market demand for increasingly greater thermal and acoustical insulation performance has resulted in the production of increasingly thicker strips of insulation felts to achieve the insulation properties desired. For shipping and handling purposes it is desirable to compress these felts and form the strips into rolls for packaging wherein the strips are greatly reduced in volume from their normal uncompressed state e.g. up to a 9 to 1 compression ratio. This reduction in volume saves on freight costs for the product and the resulting smaller diameter packages are easier to handle during shipment and at the job site. However, for insulating purposes, it is important that the strips of insulation recover to substantially their original thickness when released from the packages to thereby retain their insulating properties.
It has been found that the repeated compression, expansion and recompression of these strips of glass fiber felts in the winding and packaging operation damages the felts so that the felts do not recover as fully. Thus, in a winding and packaging operation where the strips are allowed to expand even partially after their initial compression, the recovery will be affected and to obtain a smaller diameter roll with good recovery, it is necessary to minimize any expansion of the strips of felt once the strips have been initially compressed. Otherwise, to retain the desired recovery and insulating properties for the strips, it is necessary to form larger diameter rolls thereby increasing freight costs, requiring more storage space for the product and making the product harder to handle prior to installation.
The formation of the spiral wound roll must be accomplished without the formation of a hard center core or the telescoping of the roll. If the center core is too tightly wound in an attempt to form a smaller diameter roll, the portion of the felt strip forming the core will be excessively damaged affecting its recovery and insulating properties. The smaller diameter roll must also be obtained without causing the roll to telescope at its center thereby making the roll unsuitable for packaging.
It is also important to form a roll of such dimensions that when it is packaged, the roll can be further compressed in one direction to form a readily stackable package when turned on its side. The rolls are packaged in such a way that advertising and other information appears on the circumference of the packaged roll. If the package formed from the roll is too narrow, the packages of the rolled strip insulation will not be stable for stacking and will be less acceptable in the market place where it is desirable to show the advertising and other information appearing on the circumference of the package.
In the winding machines of the prior art such as the winding machine shown and described in U.S. Pat. No. 4,928,898, the winding space is defined by three members: an infeed conveyor, an inclined conveyor and a compression roll. With this arrangement, the outer layer of the felt strip being wound onto the roll can expand after it passes the compression roll and before it passes inside the trailing portion of the felt strip being fed into the winding space. This results in an additional expansion and recompression of the felt strip which causes damage to the glass fibers in the strip and requires the formation of a larger diameter roll, if the strip is to exhibit proper recovery, than would be required if the additional expansion and recompression were eliminated or minimized. In addition, should an attempt be made to wind a roll too small in diameter with such equipment, the roll can telescope and/or have too hard a core which adversely affects the recovery of the strip of compressible material.